1. Field of the Invention
The invention relates to a vehicle and a control method for a vehicle and, more particularly, to a vehicle capable of outputting electric power of an electric power supply mounted on the vehicle to an external load or receiving electric power for charging the electric power supply mounted on the vehicle from an external electric power supply and a control method for a vehicle.
2. Description of Related Art
A vehicle in which electric power can be exchanged between an electrical load outside the vehicle or an electrical load brought into the vehicle (hereinafter, these electrical loads will be collectively referred to as an “external load”) or an electric power supply outside the vehicle (external electric power supply) and a DC electric power supply (electric power supply mounted on the vehicle) mounted on the vehicle is known.
For example, Japanese Patent Application Publication No. 2012-70577 (JP 2012-70577 A) discloses a discharging system that is capable of outputting DC electric power outside from a battery of the electric power supply mounted on the vehicle. In this discharging system, a switch (interlock relay) for preventing the voltage of the electric power supply mounted on the vehicle from being output by mistake to an external terminal is disposed on an electric power line between the battery and the external terminal (connector) to which the external load is electrically connected (refer to JP 2012-70577 A).
When switch welding (fixation in a conducting state) occurs in the switch described above, the voltage of the electric power supply mounted on the vehicle can be unintentionally applied to the external terminal. In general, welding diagnosis is performed so as to determine the presence or absence of the switch welding.
It is desirable that traveling is permitted, even if the switch welding is detected by the welding diagnosis, if safety of the external terminal is ensured. If the traveling is not permitted in every case where the result of the welding diagnosis is abnormal, the traveling may be prohibited even in a case where it can be determined that the vehicle is able to travel and the safety ensured by other means. In JP 2012-70577 A described above, a relationship between a welding abnormality of the interlock relay and determination whether to permit the vehicle to travel is not particularly studied.